The rule should be configurable. Per our conventions, we should configure it to enforce 1 space after returns, with the exception of multi-line output. E.g.,

// Good...
var v = foo();
// returns 'beep'

// Okay...
var f = beep();
/* returns
{
    ...
}
*/

// Bad...
var p = boop();
// returns             'bip'

To make this rule more specific, instead of also applying to multi-line returns annotations, instead it can only apply to // returns and // => annotations beginning with // (and // e.g., returns and // e.g., =>)